Term
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Definition
| planes are parallel if and only if they do not meet in other words they have no points in common |
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Term
| perpendicular lines to a plane |
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Definition
| a given line is perpendicular to a given plane if and only if every line in teh plane that intersects the given line is perpendicular to the given line |
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Term
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Definition
| from the Greek meaning two faces this is an angle formed by two intersecting planes |
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Definition
| the angle determined by the intersection of a plane with a dihedral angle when the plane is perpendicular to each face of the dihedral angle |
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Definition
| a dihedral angle is a right dihedral angle if and only if all of its plane angles are right angles |
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Term
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Definition
| two planes are perpendicular if and only if they form a right dihedral angle. in other words two intersecting planes are perpendicular if and only if there exists a line in one of the planes which is perpendicular to both the other plane and the line of intersection of the two planes |
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